ok, i am almost possitive on how u get ur ms dash back.. now get Forza motorsport. boot it up with the disk, and when u select ur XBox live name, go to "Create New Account" dont really create one (unless u want to) and then u when it comes to the menu when u put in all ur info, just turn off the XBox. i think this is how u get ur ms dash back
I'd just use an auto installer to reformat the MS Dash like smigs and thereturn have mentioned. I really do not think Forza motorsport is going to reinstall a screwed up MS Dash.....